Objective To study the laryngeal mask airway (LMA)replacing face mask and endotracheal intubation which was used for hypoxemia elderly patients after thoracotomy.Methods The endotracheal intubations were removed after the patients fully awake.When obsorbing oxygen through nasal oxygen tube,60 patients who suffered from serious hypoxemia for 5 minutes were divided into group A using LMA,group Busing face mask and group C using endotracheal intubations.20 cases were randomly respectively selected from A,B group.Group A used one -time 3rd or4th classic LMA,and the LMA were placed at the normal location,then connected on the ventilator or anesthesia machine let the patients breathe independently or intermittently mandatorily.Group B used face mask,and group C used LMA to control breathe.The SpO2 and the side effect under the these conditions were observed respectively at 1,3,5,10 minutes.Results The SpO2 of the three group were basically the same at 1,3 minutes, but gastric up gas, reflux, aspiration were happened to the patients of group A and group B at 5,10 minutes and the drying and pain throat was very common in group C.Conclusion From the above we can conclude that LMA can give an effectively ventilation when hypoxemia happen.